Tag Archives: NPV

Helicoverpa and NPV in Sorghum – Current Issues

As the earlier plantings of sorghum progress through flowering, moderate to high Helicoverpa pressure means that many crops have caterpillar numbers over threshold.  Nucleopolyhedrovirus (NPV) is one of the main insecticides used to control Helicoverpa larvae in sorghum, however prevailing conditions play an important role in the speed and level of control achieved with NPV.

Early Season Helicoverpa issues and the use of NPV to control larvae

Helicoverpa populations have started with a bang this season.  One or more larvae per plant are common in pre-flowering sorghum, corn and cotton. However, early flowering sorghum crops are carrying up to 10 larvae per head.  Corn and sorghum (monocot crops) host only Helicoverpa armigera, not H. punctigera – which has implications for control.  Some key issues relevant to dealing… Read more »

Bring on NPV against grubs on grain sorghum

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Every year caterpillars of the corn earworm (helicoverpa), Helicoverpa armigera, cause losses to sorghum crops. Regular inspection during flowering is important to detect caterpillar infestations and properly time control measures. Pre-flowering heads of grain sorghum are very attractive to egg-laying moths of the corn earworm. On any individual head, most eggs are laid prior to the start of flowering, as… Read more »

Getting the most from NPV sprays on grain sorghum

Some issues have recently been raised on the Darling Downs regarding the use of Helicoverpa nucleopolyhedrovirus (NPV) against corn earworm on grain sorghum. These issues involve the delay in time to kill and the level of control not necessarily meeting growers’ expectations. Seasonal conditions The last couple of weeks on the Downs have been cooler than normal. The average daily… Read more »

Friendly fighter conquers foe

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Microplitis demolitor is just one of many friendly fighters that battle to contain numbers of one of our most important pests, the corn earworm, Helicoverpa armigera. Corn earworm on grain sorghum is making its presence felt and many crops are being sprayed with Helicoverpa nucleopolyhedrovirus (NPV) to control above-threshold infestations of caterpillars. The current high value of grain sorghum (over… Read more »